Monitoring devices



United States Patent [72] Inventor David Littmann Belmont, Massachusetts [21] Appl. No. 663,423 [22] Filed Aug. 25, 1967 [45] Patented Dec. 1, 1970 [73] Assignee Minnesota Mining 8: Manufacturing Company Maplewood, Minnesota a corporation of Delaware [54] MONITORING DEVICES 3 Claims, 14 Drawing Figs. [52] U.S.Cl l8l/24 [51] Int.Cl A6111 7/02 [50] Field of Search 181/24; 128/205 56] References Cited UNITED STATES PATENTS 1,445,711 2/1923 Rayder 181/24 Primary ExaminerStephen J. Tomsky Attorney-Wolf, Greenfield & Sacks ABSTRACT: A stethoscope head made entirely of inexpensive plastic adapted for manufacture as a low cost item having a diaphragm permanently sealed at its periphery to the diaphragm of a shell. In a modification the stethoscope head is provided with an arcuately curved diaphragm adapted to conform to the body or arm of a human with tabs extending therefrom for attachment of straps whereby the stethoscope may be either attached by the straps to the body for monitoring or attached to a blood pressure monitoring cuff with provisions being made in the cuff for securing the plastic stethoscope. Clip means for a separate strap attachment to a I stethoscope head in place of the tabs are also disclosed.

Patented Dec. 1, 1970 3,543,875

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Pafented Dec. 1, 1970 3,543,875

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MONITORING DEVICES.

The present invention relates to a stethoscope head adapted for use in varying embodiments as a chestpiece unit and in other embodiments as a monitoring device for blood pressure and other monitoring purposes.

In the stethoscope art which has heretofore developed, the stethoscope chestpiece has been a highly specialized relatively expensive device to manufacture, and further is extremely limited in use. The Stethoscopes which are commonly available are primarily made of steel, aluminum or other metals, with separable diaphragms secured to the metal portions by a ring or other similar mechanisms. These Stethoscopes are consequently made of a number of different components carefully machined or shaped and fitted together. Such stethoscope heads ordinarily sell for no less than several dollars even at wholesale and therefore cannot be adapted for disposal after a single use. Further the stethoscopes heretofore available are not designed for use as a constant monitoring unit for constantly reading blood pressures or other body functions.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the foregoing limitations and other limitations of the prior art. In the present invention a simple and inexpensive stethoscope chestpiece or head formed entirely of plastic is capable of being injection-molded or vacuum-formed and because of its inexpensive construction may be disposed of after a single use. The present invention provides a stethoscope chestpiece or head which is formed with a flexible diaphragm preferably arcuate in cross section in at least one plane that is adapted to hug the arm or chest of a patient and is designed to be secured in such aposition by an integral strap or other means for constant monitoring purposes. A further object of the present invention is to provide an improved stethoscopechestpiece or head having a curved diaphragm that is adapted to closely conform to a patie'nts body or arm and thereby provide more intimate contact over a larger surface than possible in stethoscopes heretofore available. A further object of the present invention is to provide a stethoscope chestpiece or head having a diaphragm completely sealed on bonded to the shell or casing of the chestpiece or head to provide an improved air chamber that is not likely to leak and thereby adversely affect the sound being generated in the chamber. A further object of the present invention is to provide an improved diaphragm of rectangular shape having an arcuate surface that is more comfortable when attached under a blood pressure cuff. A further object of the present invention is to provide an improved blood pressure cuff and stethoscope head combination in which a stethoscope head or chestpiece is secured under a blood pressure cuff in such a manner as not to impose uncomfortable pressures upon a patients arm.

In the present invention there is provided a stethoscope chestpiece or head formed entirely of plastic, preferably molded, and consisting of a plastic shell having a periphery with an outwardly extending flange to which is sealed or bonded a diaphragm also preferably formed of plastic. The diaphragm in a preferred embodiment is arcuately shaped in one plane intersecting the diaphragm. In a preferred embodiment the diaphragm is rectangular in shape the shell is provided with tabs adapted to be secured to a blood pressure cuff or strap for attachment to a patients arm of body for monitoring purposes. Means are also provided for attachment of straps to the stethoscope chestpiece or head in the form of a continuous bent wire device bent to engage a portion of the stethoscope head.

In a further embodiment of the present invention there is provided a blood pressure cuff and stethoscope combination composed of a flexible band adapted to be wrapped about a human arm with the band having means formed in it to receive an inflatable bladder'and means forming an opening in the band to receive a stethoscope head with the stethoscope head projecting partially through the opening and partially under or in engagement with the band.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing objects and advantages of the present invention will be more clearly understood when considered in conjunction with the accompanying drawings in which:

FIG. 1 is a top plan view ofa stethoscope head embodying a preferred form of the invention,

FIG. 2 is a fragmentary cross-sectional view of the embodiment shown in FIG. 1 taken partially along the line 2-2 of FIG. 1

FIG. 3 is a cross-sectional view taken along the line 3-3 of FIG. 2,

FIG. 4 is a plan view of one side of a blood pressure cuff embodying a preferred form of a stethoscope head and showing a modification of the invention,

FIG. 5 is a plan view of the other side of the blood pressure cuff in combination with a stethoscope head showing the other side of the view illustrated in FIG. 4 and,

FIG. 6 is a cross-sectional detail of a blood pressure cuff and stethoscope head construction in somewhat schematic form taken substantially along the line 6-6 of FIG. 5,

FIG. 7 is a side elevational view ofa modified form ofthe invention,

FIG. 8 is a top plan view of the embodiment illustrated in FIG. 7,

FIG. 9 is a partially fragmented cross-sectional view of the embodiment shown in FIG. 7,

FIGS. 10, 11 and 14 are respectively top side and end elevational views of a modification of the invention and,

FIGS. 12 and 13 are cross-sectional views taken on the line 12-12 and 13-13 of FIG. 10. 5

DESCRIPTION OF PREFERRED EMBODIMENT Referring to the embodiments illustrated in FIGS. 1 to 3, there is shown a stethoscope head particularly adapted for use in connection with constantly monitoring body functions. The stethoscope head is designed to be attached to a blood pressure cuff for attachment to an arm for attachment directly to an arm or chest of a patient. The construction illustrated is fabricated preferably entirely of an injection molded or vacuum formed plastic such as polystyrene, polypropylene or the like. The head is formed with a diaphragm 10 preferably of very thin material which may, for example, be in the order of magnitude of .008 inch thick. This diaphragm is rectangular in shape but may be provided with rounded corners. The diaphragm is arcuately bent with the radius of the arc in the order of magnitude of about 1% inches to 4 inches depending These surfaces, may if desired, be tapered from a thicker portion near the center of the shell at 15 to a thinner portion at the periphery of the shell indicated at 16. The taper may for example include a thickness of .060 inch at point 15 and .040 inch at point 16. This shell is therefore much thicker and more substantial than the thickness of the diaphragm. The shell 12 is bonded or otherwise sealed to the entire periphery ll of the diaphragm 10. The bond or seal may be effected by any suitable means such for example as heat sealing or suitable cement. The center of the shell is provided with a boss or projection 20 that extends outwardly from the shell in a direction away from the inner surface 21 of the diaphragm 10. This projection 20 which is integrally formed with the shell 12 has an opening 25 that is coaxial with the axis of the diaphragm 10. The opening 25 is continuous with the opening 26 at right angles thereto which is partically formed by a tubular extension 27 also integral with the head 20. The extension 27 may be provided with a series of outwardly extending ridges 28 or grooves. A

pair of tabs 30 and 31 are integrally formed with the shell 12 at opposite sides thereof with these tabs 30 and 31 also preferably generally arcuate in shape as viewed in a plane taken longitudinally through the stethoscope head. These tabs should be in an order of thickness that is preferably somewhat thinner than the thinnest portion of the shell but thicker than the thickness of the diaphragm and thus may, for example, be in the order of magnitude .03 inch in thickness. These tabs preferably should be'somewhat narrower than the width of the shell and preferably they are provided with a series of slots 33 for receiving and securing a strap in a conventional fashion. A pair of ears 34 extend outwardly from the extreme ends of the tabs 30 and 31.

The shell 12 is somewhat dome-shaped in cross section as illustrated in FIG. 2 and provides a height from the center of the dome shape to the inner surface of the diaphragm, preferably in the order of magnitude of about one-eighth inch. Thus the stethoscope head has an air volume of irregular shape that is generally rectangular in plan view and crescent in vertical cross section.

This stethoscope head is designed for use on patients during operations and the like where it is desired to monitor the patients heart beat, blood pressure or other comparable body functions. In this arrangement the stethoscope is placed over the heart and is secured in this position by a strap passing around the slots 33. The opening 26 is connected to a conventional binaural or to another unit of similar purpose by in- 'terengaging the tubular extension 27 with a tube of a binaural.

The stethoscope head may also be secured about the arm of a patient whose blood pressure is being monitored with the unit being secured in a similar fashion. It may also be used in conjunction with the blood pressure cuff hereafter described. The unit is, as indicated above, made entirely of a plastic such as polypropylene and can be either vacuum formed or injection molded. Because of this the head is relatively inexpensive and can be discarded after a use during a single operation.

Referring to the embodiment shown in FIGS. 4 to 6, there is illustrated a stethoscope head 50 of similar design to the stethoscope described in FIGS. 1 to 3. This particular stethoscope head is used in conjunction with a specially designed blood pressure cuff. This blood pressure cuff 51 is formed of conventional cuff material. It is shaped rectangularly with the length of the rectangular shape considerably longer than the width of the rectangular shape. The cuff is provided-withsuitable pockets or receiving means to receive a conventional inflatable bladder such, for example, as the rubber bladder illustrated in dotted outline at 54. This inflatable bladder may form an integral part of the cuff, forming the outer walls of it. Alternately it may be positioned within a pocket or double lining of the cuff with the double lining illustrated in FIG. 6 at 57 and 58 with the bladder in between. Air is supplied to' this bladder through tube 59 which is integrally connected to the interior of the bladder in a conventional fashion. A second tube 60 is also similarly connected suitable for conventional blood pressure monitoring. The stethoscope head 50 extends through a hole 61 in this bladder and through a smaller coaxially alined hole 62 in the cuff material. The

boss projects through this smaller hole 62 with the larger position of the shell positioned immediately below.

and 64. These slots are parallel and positioned on opposite sides of hole 62. The tabs and 31 are retained in these slots 63 and 64 by cars 34 which project outwardly beyond the side edges of the slots 63 and 64 as is illustrated in FIG. 5. In this arrangement the tube 65 is connected to the stethoscope head 50 on the side of the cuff opposite the side that normally faces the arm.

The cuff may be secured about the arm by any suitable and conventional means. If desired a fabric engaging type of material comprising a fibrous mass 66 and a pad 67 of a plurality of minute nylon hooks may be used. Such combination of materials may comprise a commercial product sold under the mark Velcro".

Referring now to the modification illustrated in FIGS. 7 to 9 inclusive, there is illustrated a stethoscope head which may also be used as a disposable device. In this arrangement the head is particularly adapted for use either as a conventional stethoscope chestpiece adapted for disposal after a single use on an infectious patient, or with a blood pressure cuff in which the head may be secured by straps to a patient. In thisconstruction the diaphragm 71 and shell 72 are both formed of plastic preferably of the type previously described. The shell 72 preferably circular in plan view (FIG. 8), has a peripheral flange 73 and a frustoconic center segment 74. A boss 75 having a continuous convex side wall 76 is formed with a tube 77 extending radially outward. An opening 78 in the tube communicates with the interior of the stethoscope. The entire shell is molded by conventional means as an integral unit. The diaphragm 71 which is thinner than the wall of the shell is bonded or suitably sealed by cement or other means to the periphery of the shell at the peripheral flange 73 to form a somewhat conical internal air space. Preferably the diaphragm is heat sealed to the head with these components formed of .the same material.

Means 80 are provided on the head for attachment of a belt or straps so that the stethoscope head may be secured to a patient during constant monitoring procedures. This means 80 comprises a continuous resilient wire 81 formed with a center loop 82 that resiliently engages a major portion of the side wall 76 with its ends reversely bent at 83 to form opposed closed loops 84 on opposite sides of the center loop 82, thereby providing openings through which straps may be slipped.

A further modification of the invention comprises the utilization of a pressure sensitive or other suitable type of adhesive on the outer surface of the diaphragm so that the stethoscope head may be stuck directly to the patients body for monitoring purposes without the aid of auxiliary tape or clips. Thus in the embodiment principally illustrated in FIGS. 7 to 9 in place of the wire means 80 there is provided an adhesive surface 80A on the outer surface of the diaphragm 71. This adhesive surface 80A may comprise a conventional pressure sensitive adhesive ordinarily used in tapes and the like. The adhesive may be covered in a conventional fashion with a strippable paper or fabric protective covering 808 which upon removal will permit attachment directly of the stethoscope to the patients body. The protective covering may extend beyond the periphery of the diaphragm 71 at 80C so as to be gripped. This arrangement will thus assure an intimate contact between the diaphragm and the patients body.

In the embodiment of'the invention illustrated in the FIGS. 1 to 3, the tabs 30 and 31 may be eliminated and in their place the outer surface of the diaphragm 10 may be covered with a pressure sensitive or other type of adhesive as previously described. This pressure sensitive adhesive may also be covered with a protective cloth or fabric covering which extends beyond the periphery of the diaphragm.

Referring now to the embodiment of FIGS. 10 to 14, there is illustrated a disposable chestpiece which may be made of the same materials as referred to above. This chestpiece is principally useful in a disposable stethoscope and is designed for inexpensive manufacture, storage and handling. The design, nevertheless is acoustically satisfactory. In this arrangement the shell is circular in plan view as illustrated in FIG. 10. It has a shallow concave shape terminating in a continuous peripheral sidewall that in turn is continuous with outwardly extending peripheral flange 94. The outer surface of shell 90 can be reinforced with a series of integrally formed ribs 96 extending across the outer surface in a chordallike fashion. A tube '91 opening into the shell is integrally formed with it. This tube is adapted to be attached at its free end to the tubular end of a binaural. A diaphragm 97 of a thickness in the order of one-half or less of the thickness of the shell is bonded or otherwise sealed to the surface of flange 94, the back of which may be serrated or otherwise decorated. This shell and diaphragm form an enclosed air space 93 which is continuous with the interior 92 of the tube 91. In this arrangement the axis of the tube 91 extends outwardly from the shell in a plane parallel to the surface of the diaphragm 97. The diaphragm 97 may be made of the same plastic material as the shell and may be heat sealed or otherwise conventionally bonded to it. If different materials are used they should be selected so as to permit an effective attachment of the diaphragm to the shell be cement bonding or heat sealing with the requirement of a third mechanical component.

Iclaim:

l. A stethoscope chestpiece formed of a plastic material and having a flat plastic diaphragm uniformly thick and a shell, said shell having a concave wall terminating in an outwardly extending peripheral flange providing a flat, annular surface providing an area to which said plastic diaphragm may be solely secured, and said shell having an opening remote from said flange, and a tube with one end adjacent to and communicating with said opening and with its length generally parallel to said diaphragm, means permanently bonding the periphery of the diaphragm to said flat annular surface of said peripheral flange to form an enclosed air chamber between said diaphragm and concave wall, with said peripheral flange and said diaphragm forming an annular member of greater mass and rigidity than the central portion of said diaphragm.

2. A stethoscope chestpiece formed of a unitary molded head of plastic consisting of a frustoconic section having a continuous, peripheral, outwardly flared flange at its wider end, a boss closing the narrower end of said section, said boss having a tubular opening extending laterally outwardly through said boss and with a hollow, cylindrical projection forming a continuation of said opening, and a plastic diaphragm covering said wider end of said frustoconic section with the periphery of said diaphragm bonded to said flange and presenting a surface remote therefrom which is smooth and uniplanar across its entire diameter, and means for securing said chest piece comprising a clamp engaging said head with said clamp forming a pair of apertures adapted to receive and secure belt means.

3. A stethoscope as set forth in claim 2 wherein said clamp is detachable and comprises a bent wire having an intermediate section shaped to resiliently anddetachably engage said head, and the ends of said wire are reversely bent to form apertures. 

